18650 Battery Tester with Colour Display – Know the exact health of every cell
Have a box full of 18650 batteries and no idea which ones are still good? Stop guessing. With this dedicated tester, you can get accurate readings in minutes: real-world capacity in mAh, internal resistance, voltage, and current—all displayed in real-time on a crisp 1.77-inch colour screen.
Note: The module features two separate slots—one for powering the device and one for the cell under test. Please note that data is stored in volatile memory and will reset if the device is powered off.
Why choose this tester? (Key Advantages):
- Real capacity, not estimates — measures the actual mAh and mWh delivered by the cell, rather than relying on theoretical voltage-based calculations.
- Automatic internal resistance — displayed instantly upon inserting the cell, with no extra buttons or steps required.
- Three operating modes — choose between charge, discharge, and auto-cycle (repetitive charge-discharge) for comprehensive testing or quick checks.
- Selectable discharge current — toggle between 0.5A and 1A depending on your cell specifications or testing requirements.
- Dual USB Type-C ports — one for power input and one for external power output.
- 10W load resistor — efficiently dissipates heat during discharge without overloading internal components.
- Perfect for DIY, power banks, and inventory sorting — easily identify degraded cells before building battery packs or starting your next project.
Performance and Specifications
The tester can be powered via 5V DC USB Type-C or directly from an 18650 cell inserted into the power slot. The charging current is fixed at 1A, while the discharge current can be set to 0.5A or 1A via the menu. The discharge cut-off voltage is adjustable between 2.5V and 3.5V (default 3.0V) for custom testing. The measurement range covers 0–99999 mAh and 0–99999 mWh, suitable for any standard commercial cell. Please note: the discharge resistors will get hot during operation—always use the device in a well-ventilated area and do not cover it.
| Parameter | Value / Detail |
|---|---|
| Supported Cell Type | 18650 Li-ion |
| Power Supply | 5V DC – USB Type-C or 18650 cell |
| Charging Current | 1A (max) |
| Discharge Current | 0.5A or 1A (selectable) |
| Discharge Cut-off Voltage | 3.0V fixed or 2.5–3.5V adjustable |
| Measured Capacity | 0–99999 mAh / 0–99999 mWh |
| Internal Resistance | Automatic, ~±10% error margin |
| Display | 1.77-inch colour, real-time data |
| USB Type-C Ports | 2 (power input + external discharge) |
| Load Resistor | 10W |
| Operating Modes | Charge / Discharge / Auto-cycle |
| Memory | Volatile – resets upon power-off |
Programming and Usage Instructions
- Insert an 18650 cell into the power slot or connect a power source via USB Type-C.
- Insert the battery to be tested into the test slot—the internal resistance will appear automatically.
- Navigate the menu to select your operating mode: charge, discharge, or auto-cycle.
- Set your discharge current (0.5A or 1A), cut-off voltage, and the number of cycles if using the auto-cycle mode.
- Press Start/Stop and monitor the real-time values on the colour display.
- Once the test is complete, the status LED will signal the end of the cycle, allowing you to read the total capacity and determine the cell’s condition.
Package Contents
- 1x 18650 Battery Tester with 1.77″ Colour Display
Frequently Asked Questions
Does the tester work without a cell in the power slot?
Yes. It can be powered directly via the 5V USB Type-C port without needing a cell in the power slot.
Can I use this with other battery types?
No. This device is designed exclusively for 18650 Li-ion cells. Using other battery types may damage the unit.
What happens to my data if I turn off the tester before the test finishes?
The memory is volatile, meaning all measured values will be cleared if the device is powered down. You will need to restart the test from the beginning.
How accurate is the internal resistance measurement?
The error margin is approximately ±10%. This is sufficient for separating healthy cells from degraded ones, though it is not a substitute for a laboratory-grade milliohmmeter.
Is it normal for the tester to get warm during use?
Yes. The 10W discharge resistors generate heat during operation. Please ensure the device is used in a well-ventilated area and never covered while in use.
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